Gosh Darnit !!
Takes lot of time to draw a road-book ... and I'm lucky I discovered the Google Maps application
Thank you guys for all your inputs.
For those interested here comes a first draft of the route form Portsmouth to Kendall (SE entry of the Lake District).
Feel free to give some hints
Wharf Rd � Kendal, Cumbrie, Royaume-Uni - Google Maps
Thanks Mark Manley

but you advised me to ride the "Fosse way" [A 429] and even if I can admit that I like a bit of History and a lot of Architecture that looks like a damn straight road

so I took a bit left of it

on B-class road.
Am I wrong ? Watcha think ?
At that point, maybe I should sleep somewhere between Stratford-Upon-Aven and Hinckley. What about Coventry ?
I routed via Hinckley, but I don't ride a Triumph so I hope nobody will throw rocks at me
Then ride North through the "Peak District". There I didn't routed via the "Snake Road", am I missing something ?
Continue to ride North to "Lake District" via "Yorkshire Dales" and Richmond for a bit of boots' lust (I'm working of my feminine side

).
To this point, Google tells me 736 kms / 457 miles, and 14 hours.
Do you think this is accurate ?
I was thinking of reaching Kendall in 2 days, it would means around 400 kms / 240 miles per day...
Am I out of my mind ?
Cheers
Greg